Jupil Ko

Comparison Between Single and Combined Clinical Postural Stability Tests in Individuals With and Without Chronic Ankle Instability.

Objective: To determine if a single or/and combined clinical tests match group membership based on self-reported ankle function. Design: Cross-sectional. Setting: Biomechanics Laboratory. Participants: From participants, 58 meeting inclusion/exclusion criteria were divided into a chronic ankle instability (CAI) group (n = 25) who reported ⩽25 on the Cumberland Ankle Instability Tool (CAIT) and a history of moderate–severe ankle sprain(s) and a control group (n = 33) who reported ≥29 on the CAIT and no history of ankle sprain(s). Interventions: Participants completed the following clinical tests: Foot Lift Test (FLT), the Star Excursion Balance Test (SEBT), the Single-Leg Hop Test (SLHT), and the Time in Balance Test (TIB) in a randomized order. A linear regression model was applied to determine measures that matched ankle group membership. Main Outcome Measures: The mean of SEBT reach distance was normalized to percentage leg length. The mean of number of errors in the FLT was recorded. The SLHT and TIB were reported as time in seconds, and the means were calculated. Results: The most parsimonious combination of tests (SLHT and SEBT) resulted in correctly matching 70.69% (41/58) of participants into groups, which was significantly better than chance. The multiple correlation coefficients (R value) for combining the SLHT and SEBT was 0.39. Conclusions: Using SLHT and SEBT resulted in improved recognition of participants designated into the CAI or control groups. Self-report perception of ankle function provides limited information for clinicians and researchers. Using multiple clinical function tests may be more helpful in determining deficits and intervention effectiveness.

Does chronic ankle instability influence lower extremity muscle activation of females during landing

Much remains unclear about how chronic ankle instability (CAI) could affect knee muscle activations and interact with knee biomechanics. Therefore, the purpose of this study was to assess the influence of CAI on the lower extremity muscle activation at the ankle and knee joints during landings on a tilted surface. A surface electromyography system and two force plates were used to collect lower extremity muscle activation of 21 young female individuals with CAI and 21 pair-matched controls during a double-leg landing with test limb landing on the tilted surface. In the pre-landing phase, compared to controls, CAI participants displayed a reduced ankle evertor activation that could place CAI at a high risk of giving way or sprain injury. In the landing phase, an increased tibialis anterior activation of CAI led to increased co-contraction of ankle muscles in the sagittal and frontal plane. A greater ankle muscle co-contraction could increase the ankle stability during landings but may adversely influence the knee muscle activations (e.g., a greater co-contraction ratio of quadriceps to hamstrings). Relevant training programs (e.g., increasing pre-landing peroneal activation, and optimizing activation ratio of quadriceps to hamstrings) may help individuals with CAI improving ankle stability and reduce atypical knee loading during landings.

An Evaluation of Portable Wet Bulb Globe Temperature Monitor Accuracy

CONTEXT   Wet bulb globe temperature (WBGT) is the gold standard for assessing environmental heat stress during physical activity. Many manufacturers of commercially available instruments fail to report WBGT accuracy. OBJECTIVE   To determine the accuracy of several commercially available WBGT monitors compared with a standardized reference device. DESIGN   Observational study. SETTING   Field test. PATIENTS OR OTHER PARTICIPANTS   Six commercially available WBGT devices. MAIN OUTCOME MEASURE(S)   Data were recorded for 3 sessions (1 in the morning and 2 in the afternoon) at 2-minute intervals for at least 2 hours. Mean absolute error (MAE), root mean square error (RMSE), mean bias error (MBE), and the Pearson correlation coefficient ( r) were calculated to determine instrument performance compared with the reference unit. RESULTS   The QUESTemp° 34 (MAE = 0.24°C, RMSE = 0.44°C, MBE = -0.64%) and Extech HT30 Heat Stress Wet Bulb Globe Temperature Meter (Extech; MAE = 0.61°C, RMSE = 0.79°C, MBE = 0.44%) demonstrated the least error in relation to the reference standard, whereas the General WBGT8778 Heat Index Checker (General; MAE = 1.18°C, RMSE = 1.34°C, MBE = 4.25%) performed the poorest. The QUESTemp° 34 and Kestrel 4400 Heat Stress Tracker units provided conservative measurements that slightly overestimated the WBGT provided by the reference unit. Finally, instruments using the psychrometric wet bulb temperature (General, REED Heat Index WBGT Meter, and WBGT-103 Heat Stroke Checker) tended to underestimate the WBGT, and the resulting values more frequently fell into WBGT-based activity categories with fewer restrictions as defined by the American College of Sports Medicine. CONCLUSIONS   The QUESTemp° 34, followed by the Extech, had the smallest error compared with the reference unit. Moreover, the QUESTemp° 34, Extech, and Kestrel units appeared to offer conservative yet accurate assessments of the WBGT, potentially minimizing the risk of allowing physical activity to continue in stressful heat environments. Instruments using the psychrometric wet bulb temperature tended to underestimate WBGT under low wind-speed conditions. Accurate WBGT interpretations are important to enable clinicians to guide activities in hot and humid weather conditions.

Cross-cultural adaptation, reliability, and validation of the Korean version of the identification functional ankle instability (IdFAI)

Abstract Purpose: To cross-culturally adapt the Identification Functional Ankle Instability for use with Korean-speaking participants. Methods: The English version of the IdFAI was cross-culturally adapted into Korean based on the guidelines. The psychometric properties in the Korean version of the IdFAI were measured for test-retest reliability, internal consistency, criterion-related validity, discriminative validity, and measurement error 181 native Korean-speakers. Results: Intra-class correlation coefficients (ICC2,1) between the English and Korean versions of the IdFAI for test–retest reliability was 0.98 (standard error of measurement = 1.41). The Cronbach’s alpha coefficient was 0.89 for the Korean versions of IdFAI. The Korean versions of the IdFAI had a strong correlation with the SF-36 (rs = −0.69, p < .001) and the Korean version of the Cumberland Ankle Instability Tool (rs = −0.65, p < .001). The cutoff score of >10 was the optimal cutoff score to distinguish between the group memberships. The minimally detectable change of the Korean versions of the IdFAI score was 3.91. Conclusion: The Korean versions of the IdFAI have shown to be an excellent, reliable, and valid instrument. The Korean versions of the IdFAI can be utilized to assess the presence of Chronic Ankle Instability by researchers and clinicians working among Korean-speaking populations. Implications for rehabilitation The high recurrence rate of sprains may result into Chronic Ankle Instability (CAI). The Identification of Functional Ankle Instability Tool (IdFAI) has been validated and recommended to identify patients with Chronic Ankle Instability (CAI). The Korean version of the Identification of Functional Ankle Instability Tool (IdFAI) may be also recommend to researchers and clinicians for assessing the presence of Chronic Ankle Instability (CAI) in Korean-speaking population.

Functional performance tests identify lateral ankle sprain risk: A prospective pilot study in adolescent soccer players

Determining the clinical utility of functional performance tests (FPTs) and establishing cutoff scores could be useful in identifying those athletes who could benefit from effective injury prevention interventions. Our purpose was to determine the accuracy of FPTs in identifying adolescent athletes who go on to experience lateral ankle sprain(s) and establish specific cutoff scores capable of identifying those who sustain a lateral ankle sprain in the near future. Sixty‐four participants (age = 15.5 ± 1.3 years; height = 161.7 ± 7.7 cm; mass = 57.1 ± 8.4 kg) were recruited from a junior soccer club and tracked for 10 months. Participants performed the anterior (AN), posterior‐medial (PM), and posterior‐lateral (PL) reach directions of the Star Excursion Balance Test (SEBT) and the Single‐Leg Hop Test (SLHT) in pre‐season, and then were followed for the 10‐month competitive season (12 injured, 52 uninjured). Significant Area Under the Curve (AUC) values and cutoff scores were found for the PM (AUC = 0.78; 95% CI 0.61‐0.95; P = 0.003; Sn = 0.83; Sp = 0.77; cutoff = 76%) and the PL (AUC = 0.82; 95% CI 0.71‐0.94; P = 0.001; Sn = 0.92; Sp = 0.65; cutoff = 70%) reach directions of the SEBT and the SLHT (AUC = 0.77; 95% CI 0.60‐0.95; P = 0.003; Sn = 0.67; Sp = 0.94; cutoff = 15.4 seconds). The PM and PL reach directions of the SEBT and the SLHT may be useful as pre‐season screening measures to help clinicians identify adolescents who will go on to experience a lateral ankle sprain.

Functional performance deficits in adolescent athletes with a history of lateral ankle sprain(s)

OBJECTIVE To determine if adolescent athletes with a history of lateral ankle sprain(s) (LAS) displayed deficits on functional performance tests (FPTs) and if deficits on FPT were related to the number of previous LAS. DESIGN Cross-sectional study. SETTING Biomechanics Laboratory. PARTICIPANTS The injured group (n = 24) had a history of ≥1 moderate-severe LAS. The uninjured group (n = 34) had no history of LAS. MAIN OUTCOME MEASURE(S) The average reach distance of three trials in each direction of the star excursion balance test (SEBT) was normalized to leg length (%). The average of two trials of single-leg-hop test (SLHT) was calculated in seconds. RESULTS The injured group performed significantly worse in 3 directions of SEBT than the uninjured group (P < 0.05). SLHT was significantly slower in the injured group compared to the uninjured group (P < 0.05). Statistically significant, strong to moderate inverse relationships were found between the numbers of LAS and each of the three directions of the SEBT (P ≤ 0.01). No relationship was revealed between the number of LAS and the SLHT (P > 0.05). CONCLUSION(S) Adolescent athletes with a history of LAS exhibit functional performance deficits on the SEBT and SLHT. Therefore, the SEBT and SLHT may provide clinicians cost- and time-effective objective tools.

Biomechanics of ankle giving way: A case report of accidental ankle giving way during the drop landing test

Background Several case studies observed that the lateral ankle sprain resulted from a sudden increase in ankle inversion accompanied by internal rotation. However, without sufficient ankle kinetics and muscle activity information in the literature, the detailed mechanism of ankle sprain is still unrevealed. The purpose of our case report is to present 2 accidental ankle giving way incidents for participants with chronic ankle instability (CAI) and compare to their normal trials with data of kinematics, kinetics, and electromyography (EMG). Case description Two young female participants accidentally experienced the ankle giving way when landing on a 25° lateral-tilted force plate. 3D kinematics, kinetics, and muscle activity were recorded for the lower extremity. Qualitative comparisons were made between the giving way trials and normal trials for joint angles, angular velocities, moments, centers of pressure and EMG linear envelopes. Results One participants giving way trial displayed increased ankle inversion and internal rotation angles in the pre-landing phase and at initial contact compared to her normal trials. Another participants giving way trial exhibited greater hip abduction angles and delayed activation of the peroneus longus muscle in the pre-landing phase versus her normal trials. Conclusion A vulnerable ankle position (i.e., more inverted and internally rotated), and a late activation of peroneus activity in the pre-landing phase could result in the ankle giving way or even sprains. A neutral ankle position and early activation of ankle evertors before landing may be helpful in preventing ankle sprains.

Does Chronic Ankle Instability Influence Knee Biomechanics of Females during Inverted Surface Landings

The primary purpose of the study was to determine whether atypical knee biomechanics are exhibited during landing on an inverted surface. A seven-camera motion analysis system and two force plates were used to collect lower extremity biomechanics from two groups of female participants: 21 subjects with chronic ankle instability (CAI) and 21 with pair-matched controls. Subjects performed ten landings onto inverted and flat platforms on the CAI/matched and non-test limbs, respectively. Knee and ankle joint angles, joint angular displacements, joint moments and eccentric work were calculated during the landing phase and/or at the initial contact. Paired t-tests were used to compare between-group differences (p<0.05). We observed that CAI group displayed a significantly increased knee flexion angle, knee flexion displacement, peak knee extension moment and internal rotation moment, and eccentric work in the sagittal plane, possibly due to altered ankle biomechanics. Participants with CAI employed some compensatory strategy to improve their ankle and postural stability during landing onto the tilted surface. The increased knee extension and internal rotation moments of CAI participants could potentially result in a greater ACL loading. In future studies, it may be worthwhile to measure or estimate the ACL loading to confirm whether CAI could relate to the mechanism of ACL injury.

The relationship between acute pain and dynamic postural stability indices in individuals with patellar tendinopathy

BACKGROUND Patellar tendinopathy is a common condition resulting in persistent pain, frequently reported during physical activity. The relationship between dynamic postural stability and pain in these individuals is unclear and how it may affect postural stability. RESEARCH QUESTION Is there a relationship between acute pain and dynamic postural stability indices in individuals with patellar tendinopathy? METHODS Twenty-two recreationally active individuals with patellar tendinopathy participated. Participants performed a two-legged jump and landed on a single test-limb on a force platform. They completed 100 mm visual analogue scales (VAS) before and after landing trials. Anterior-posterior (APSI), medial-lateral (MLSI), vertical (VSI), and composite (DPSI) stability indices were calculated from ground reaction force data. The relationship between stability indices and VAS for pain as well as pain change scores were assessed via non-parametric Spearmans rho (ρ) rank correlations (p≤.05). RESULTS Baseline pain was not significantly correlated with any stability indices. Post-landing pain was significantly correlated with MLSI (ρ = 0.540, p = 0.004) while, VSI (ρ = 0.353, p = 0.053) and DPSI (ρ = 0.347, p = 0.057) had moderate, yet insignificant correlations. Pain change scores demonstrated a large correlation with MLSI (ρ = 0.598, p = 0.002). SIGNIFICANCE As pain increased in individuals with patellar tendinopathy, dynamic postural stability indices values increased, indicating more difficulty transitioning from a dynamic to static state. Although balance deficits are not typically associated with patellar tendinopathy, it appears pain and dynamic postural stability may be related in these individuals.BACKGROUND Patellar tendinopathy is a common condition resulting in persistent pain, frequently reported during physical activity. The relationship between dynamic postural stability and pain in these individuals is unclear and how it may affect postural stability. RESEARCH QUESTION Is there a relationship between acute pain and dynamic postural stability indices in individuals with patellar tendinopathy? METHODS Twenty-two recreationally active individuals with patellar tendinopathy participated. Participants performed a two-legged jump and landed on a single test-limb on a force platform. They completed 100 mm visual analogue scales (VAS) before and after landing trials. Anterior-posterior (APSI), medial-lateral (MLSI), vertical (VSI), and composite (DPSI) stability indices were calculated from ground reaction force data. The relationship between stability indices and VAS for pain as well as pain change scores were assessed via non-parametric Spearmans rho (ρ) rank correlations (p≤.05). RESULTS Baseline pain was not significantly correlated with any stability indices. Post-landing pain was significantly correlated with MLSI (ρ = 0.540, p = 0.004) while, VSI (ρ = 0.353, p = 0.053) and DPSI (ρ = 0.347, p = 0.057) had moderate, yet insignificant correlations. Pain change scores demonstrated a large correlation with MLSI (ρ = 0.598, p = 0.002). SIGNIFICANCE As pain increased in individuals with patellar tendinopathy, dynamic postural stability indices values increased, indicating more difficulty transitioning from a dynamic to static state. Although balance deficits are not typically associated with patellar tendinopathy, it appears pain and dynamic postural stability may be related in these individuals.

Cross-cultural adaptation and validation of an ankle instability questionnaire for use in Chinese-speaking population

Background The Identification of Functional Ankle Instability (IdFAI) is a valid and reliable tool to identify chronic ankle instability; however, it was developed in English, thus limiting its usage only to those who can read and write in English. The objectives of our study were to (1) cross-culturally adapt a Chinese (Mandarin) version of the IdFAI and (2) determine the psychometric properties of the Chinese version IdFAI. Methods The cross-cultural adaptation procedures used by the investigators and translators followed previously published guidelines and included 6 stages: (1) initial translation, (2) synthesis of the translations, (3) back translation, (4) developing the pre-final version for field testing, (5) testing the pre-final version, and (6) finalizing the Chinese version of IdFAI (IdFAI-C). Five psychometric properties of the IdFAI-C were assessed from results of 2 participant groups: bilingual (n = 20) and Chinese (n = 625). Results A high degree of agreement was found between the English version of IdFAI and IdFAI-C (intra-class correlation2,1 = 0.995). An excellent internal consistency (Cronbachs α = 0.89), test–retest reliability (intra-class correlation2,1 = 0.970), and construct validity (r(625) = 0.67) was also found for the IdFAI-C. In addition, the results of exploratory and confirmatory factor analysis indicated that ankle instability was the only construct measured from the IdFAI. Conclusion The IdFAI-C is a highly reliable and valid self-report questionnaire that can be used to assess ankle instability. Therefore, we suggest that it can be used to effectively and accurately assess chronic ankle instability in clinical settings for Chinese-speaking individuals.